Conventional bedding foundations such as box springs typically include an array or matrix of springs, a wooden base and an upper grid including a generally rectangular border wire. The springs may be coil springs or modular springs. The components are commonly shipped from a spring manufacturer to a box spring manufacturer separately. Once the components arrive at the box spring manufacturer's facility, the box spring manufacturer attaches the lower ends of the springs which extend downwardly from an upper wire grid assembly to a base. Padding and a cover is applied by the box spring manufacturer as desired. Such conventional bedding foundations are large and cumbersome to handle in storage, transportation or shipment which, of course, increases the ultimate cost.
Moreover, it is not uncommon for a coil spring manufacturer to compress or deform coil springs units layered one on top of the other into condensed or compacted multilayered packs for shipment to a box spring manufacturer. The aforementioned step is performed by means of a press machine enabling the foundation units to be compressed to reduce their height dimension. The coil spring units of each pack are held in their compacted state against return to their normal or unstressed condition by means of strapping applied about the unit. The spring units of each pack being compressed, the strapping is under a great amount of tension. When the packs arrive at the place of the manufacturer, it is, of course, necessary to sever the strapping around the packs in order to release the spring units for installation into box springs or mattresses. This, of course, is difficult because of the high degree of tension to which the strapping is subjected by the compression of the coil springs.
U.S. Pat. No. 4,377,279 discloses a wire foundation unit for a box spring which may be shipped to a box spring manufacturer in a collapsed condition. The manufacturer would erect the foundation wires and then fix by staples, rigid struts between the wire unit and base to permanently secure the wire unit in the erected position. The box spring manufacturing process is completed by providing the conventional layer of padding on the top of the wire foundation and a sheet covering or casing about the entire unit. However, once the manufacture is completed, the box spring is no longer collapsible and thus must be shipped in its expanded or full-size state to the point of retail or use whereby the same storage and shipment costs result at this point as with conventional box springs.
U.S. Pat. No. 4,654,905 discloses another collapsible bedding foundation for a box spring which can be shipped to a box spring manufacturer in a collapsed condition. The box spring manufacturer would erect the collapsed bedding foundation before applying padding on the top of the erected bedding foundation and covering or casing the entire unit. The collapsible bedding foundation disclosed in this patent utilizes a hinge to connect two sections of the bedding foundation so that, when collapsed, one section may overlay the other section. One drawback to this bedding foundation is that the hinge is expensive, thereby adding substantial cost to the manufacturer of the collapsible bedding foundation which is in turn passed on to the manufacturer of the box spring.
Another problem with collapsible bedding foundations, such as that of U.S. Pat. No. 4,654,905, is a reduced amount of support between the first and second sections of the foundation that are foldable relative to one another. For example, standard non-foldable bedding foundations include a solid one-piece base, such as a substantially rectangular wood frame, which provides support throughout the entire structure of the bedding foundation. However, bedding foundations that are foldable include at least two frames, one for each of the two sections of the foundation. As a result, an area including a “gap” is formed between the two sections of the foundation. This gap is not necessarily a discernable space (although it may be), but is the area between the portions of the first and second sections which confront one another. The gap may represent a point of weakness between the two sections, which may be discernable to a user of the bedding foundation, or may serve as a point for collapse of the bedding foundation following repeated use. This reduced support affects the center of the bedding foundation, as well as the stability of the unit as a whole.
Therefore, there is a need for a collapsible box spring which is less expensive to manufacture than known collapsible box springs. There is further a need for an affordable box spring which may be collapsed after being upholstered. And there is a further need for a box spring that is collapsible while still providing adequate support to a user, particularly at or near the gap between the two sections of the box spring.